Concrete Mix For Floor Slab

  • The concrete mix for floor slab should satisfy the compressive strength requirements (normally 3000 pounds per square inch) without measures that leads to unnecessary shrinkage. Due to water increases shrinkage and cracking, a plasticizer should be applied to attain necessary slump. In order to avoid plastic shrinkage cracking, the fibers should be applied. Greater strength and entrained air are necessary for exterior slabs which are uncover to freezing weather or deicing chemicals.
  • Refrain from using extra water at the jobsite exceeding 1 to 2 gallons per cubic yard. When extra slump is required, consult with the mixer truck driver regarding the quantity of water to be added without taking the concrete out of specification.
  • It is suggested to allocate the concrete around the slab area as close to its final position as possible, and then rake it into position. To consolidate low-slump mixes, a handheld vibrator or a vibratory screed should be used. To label the surface, finish with the least amount of force and strokes of the float.
  • The control joints should be formed no farther apart than 24 to 30 times the slab thickness and under no circumstances exceeding 15 feet along both the width and length of the slab by pushing a 1-inch deep grooving tool into the surface.
  • If the joint spacing surpasses 15 feet, the load transfer devices like dowels or dowel plates should be utilized. For slabs with long joint spacing or no joints, steel reinforcement is necessary. Though, it can raise the scope for random cracking, but it will retain cracks firmly to maintain good structural performance.